This one is to replace the server that gathers my email from the umpteen addresses I've accumulated over the last 25 years, despams it and arranges it nicely for me to read ... or delete.
I used one of the 8gb Sandisk cards, and after several different atttempts at powering it, I eventually found something that works. Yes, the Pi is a bit fussy about its power. I give it 5 volts, and 4.25 appears on the voltage measuring points. Right now, I'm giving it 6 volts, and it says it's getting 5.5, wihch it seems happy with.
In the course of setting this up, I discovered that one of my mail servers has an umpty drive, which has been giving problems over the last three weeks, without me noticing. As a result, there was a huge buildup on email on one of my other servers (they send each other email all the time, don't ask).
So I rebooted the server with the disk problem the disk problem went away, and a flood of pent-up email descended (mostly, trying to tell me about various problems that I'd dealt with already in the last three weeks). Eventually, I cleared it all, and now the email-gatherer seems to be working fine. I had lots of fun trying to ensure that reverse DNS works - wiothout that, AOL and Comcast won't accept email from me. I have it partially working, I'm not sure what the remaining problem is, but AOL seems happy.
More hardware arrived today; a USB device that you can put a couple of hard drives in.m Now I need to work out who to use it. Also, some more powered USB hubs arrived; these come with a power supply. They'll be useful for powering Pies and for those Pies that beed to connect to a lot of USB things.
I think the next server for replacement will be the one with the umpty drive. You know it makes sense.